Research in this project is directed toward (1) an understanding of the mechanisms that enable living cells and tissues to utilize metabolic energy for the transport of ions across membranes, (2) the control of metabolic processes by ion transport and the ionic environment, and (3) the role of hormones in the regulation of ion transport processes. Studies will focus on (1) the separation and electron-microscopic and cytochemical identification of the various cell types of transporting epithelial tissues, (2) the separation and electron-microscopic identification of the luminal and contraluminal membranes of these cells, (3) the biochemical characterization of the transport-related activities of these cells and membranes, and (4) a variety of epithelial tissues so as to be able to correlate ion transport with metabolism among as well as within tissues. In summary, we are trying to understand transport-related metabolism and hormonal control of this metabolism at the subcellular level.